A tank truck is known from DE 20016410 U that has multiple compartments, each of which is provided with a valve used for filling and draining the respective compartment. One fill-level sensor is provided in each of the compartments, and the fill-level sensors are connected to a computer that calculates the quantities filled into and dispensed from the individual compartments. This computer is connected via a wireless transmission link to a control unit having display and input elements for monitoring and controlling the filling and draining of the tanks at a filling station, and by means of which the necessary operations such as actuation of the valves may be monitored.
However, this approach has the disadvantage that the fill level can be monitored only in an indirect manner. The possibility of avoiding overfilling depends on the interaction between the fill-level indicator and the computer, for which the algorithms corresponding to the particular compartments or tanks must be entered into the computer memory. Since the compartments or tanks of a tank truck usually do not have simple shapes that can be easily calculated, inaccuracies usually occur as a result.
During filling of tanks at filling stations, there is always the problem that overfilling of the tanks, usually underground, must be avoided for environmental reasons. For this purpose optical or thermistor threshold sensors are provided that must be observed to prevent excess fuel from entering the tanks at the filling station. However, this involves uncertainty.